首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   53138篇
  免费   3582篇
  国内免费   184篇
耳鼻咽喉   601篇
儿科学   1069篇
妇产科学   792篇
基础医学   6792篇
口腔科学   693篇
临床医学   4897篇
内科学   12864篇
皮肤病学   533篇
神经病学   5192篇
特种医学   2101篇
外科学   8501篇
综合类   587篇
一般理论   65篇
预防医学   3657篇
眼科学   926篇
药学   3187篇
中国医学   49篇
肿瘤学   4398篇
  2024年   42篇
  2023年   287篇
  2022年   601篇
  2021年   1438篇
  2020年   901篇
  2019年   1296篇
  2018年   1644篇
  2017年   1123篇
  2016年   1204篇
  2015年   1442篇
  2014年   2165篇
  2013年   2515篇
  2012年   4332篇
  2011年   4293篇
  2010年   2404篇
  2009年   2151篇
  2008年   3760篇
  2007年   3870篇
  2006年   3742篇
  2005年   3685篇
  2004年   3285篇
  2003年   3031篇
  2002年   2742篇
  2001年   317篇
  2000年   224篇
  1999年   325篇
  1998年   487篇
  1997年   439篇
  1996年   356篇
  1995年   324篇
  1994年   251篇
  1993年   236篇
  1992年   142篇
  1991年   126篇
  1990年   113篇
  1989年   95篇
  1988年   87篇
  1987年   69篇
  1986年   75篇
  1985年   100篇
  1984年   121篇
  1983年   105篇
  1982年   136篇
  1981年   109篇
  1980年   95篇
  1979年   42篇
  1978年   60篇
  1977年   57篇
  1976年   49篇
  1975年   40篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
PURPOSE: This article provides a review of the disarticulation resection of the mandible for various benign and malignant tumors and non-neoplastic processes. In so doing, the author proposes a classification to describe extension of pathology into the condylar region, thereby requiring its sacrifice. Recommendations are also proposed for preservation versus sacrifice of the meniscus when performing a disarticulation resection of the mandible. Finally, complications are evaluated in this type of mandibular resection. PATIENTS AND METHODS: This review is based on the author's accumulated clinical data obtained from performing disarticulation resections on 16 patients who presented with 10 different pathologic diagnoses. Disarticulation resections are performed for 3 different patterns of extension of pathologic processes into the condylar region, designated as type I, type II, and type III by the author. These designations reflect the radiographic involvement of the condyle or subcondylar region of the mandible by the pathologic entity. The designations of type II and type III extensions are diagnosis dependent, whereas type I extension is independent of diagnosis. RESULTS: Five patients in this series presented with type I condylar extension, 2 patients presented with type II condylar extension, and 9 patients presented with type III condylar extension. The meniscus required sacrifice in 3 of the 16 patients. Complications occurred in 3 of 16 patients and included 1 dislocation of the plate into the middle cranial fossa, 1 dislocation of the plate inferiorly and posteriorly to the mastoid process, and 1 cutaneous exposure of the plate. CONCLUSIONS: Disarticulation resections are rarely required variants of segmental resection of the mandible, and they are required by a variety of pathologic processes of the jaws and contiguous structures. The placement of a reconstruction bone plate with an affixed condylar prosthesis is well tolerated by patients and is associated with few complications. These reconstruction bone plates favorably support facial form, symmetry, and occlusion such that many patients delay their definitive bony reconstruction. Because these condyles are temporary prostheses, the surgeon should consider their removal with bony reconstruction of the disarticulation defect as soon as possible after the ablative surgery.  相似文献   
93.
The purpose of this study is to describe a subset of atypical hepatic hemangiomas that enhance rapidly and diffusely and to determine whether heavily T2-weighted images could distinguish between atypically enhancing liver hemangiomas and hypervascular malignancies. A retrospective search of MR records identified seven patients with liver hemangiomas that demonstrated diffuse early enhancement and 23 patients with biopsy-proven malignant liver lesions that were hypervascular on dynamic gadolinium-enhanced MR images. Quantitative analysis of signal intensity measurements was performed on the T2-weighted images, heavily T2-weighted (TE < 140), and dynamic gadolinium-enhanced images. Blinded reader comparison of the T2-weighted images and gadolinium-enhanced images was performed. Hypervascular hemangiomas enhanced to a greater degree than hypervascular malignant liver lesions on the early phase gadolinium-enhanced images. Perilesional parenchymal enhancement was demonstrated in five cases of rapidly enhancing hemangiomas. Signal intensity and contrast-to-noise ratios on the heavily T2-weighted images of the hemangiomas were significantly greater than that of the hypervascular malignant lesions (P < .05). Hemangiomas were differentiated from the hypervascular malignant liver lesions with high accuracy (97–100%) by three blinded readers based on the T2-weighted images. A subset of hemangiomas have atypical rapid diffuse enhancement on dynamic gadolinium-enhanced images. These atypical hemangiomas can be distinguished from hypervascular malignant liver lesions on T2-weighted MR images.  相似文献   
94.
95.
96.
The aim of this study was to investigate whether individualized tailor-made behavioural treatment based upon a problem analysis of each case was more effective than a standardized behavioural treatment protocol. Twenty-two obsessive-compulsive patients were randomly assigned to two treatment conditions: (1) tailor-made cognitive behavioural therapy and (2) standardized exposure in vivo therapy. Treatment in both conditions led to significant improvements on obsessive-compulsive targets and on the Maudsley Obsessional-Compulsive Inventory. Improvement generalized to general levels of psychopathology, depressed mood and social anxiety. Contrary to expectations the individualized treatment was not more effective than the standardized exposure therapy.  相似文献   
97.
Parkinson's disease (PD) is a major cause of disability. To date, there have been no large-scale efforts to measure the quality of PD care because of a lack of quality indicators for conducting an explicit review of PD care processes. We present a set of quality indicators for PD care. Based on a structured review of the medical literature, 79 potential indicators were drafted. Through a two-round modified Delphi process, an expert panel of seven movement disorders specialists rated each indicator on criteria of validity, feasibility, impact on outcomes, room for improvement, and overall utility. Seventy-one quality indicators met validity and feasibility thresholds. Applying thresholds for impact on outcomes, room for improvement, and overall utility, a subset of 29 indicators was identified, spanning dopaminergic therapy, assessment of functional status, assessment and treatment of depression, coordination of care, and medication use. Multivariable analysis showed that overall utility ratings were driven by validity and impact on outcomes (P < 0.01). An expert panel can reach consensus on a set of highly rated quality indicators for PD care, which can be used to assess quality of PD care and guide the design of quality improvement projects.  相似文献   
98.
99.
OBJECTIVE: Given the limited availability of small-sized cryopreserved pulmonary homografts, we implanted a series of Shelhigh No-React porcine pulmonic valve conduits (SPVC). The aim of this study was to evaluate the short-term performance following implantation. METHODS: From February 2000 to September 2000, the SPVC was implanted 25 times in 24 patients in the right ventricular outflow tract (RVOT) to correct congenital anomalies. The anatomical malformations were TOF/PA in eight patients, TGA/VSD/PS in four, truncus arteriosus in four, IAA/VSD/AS or AA in four, l-TGA/VSD in two and other in two. Age at operation was 2.8+/-3.9 years (mean+/-SD), including 12 patients under 1 year. The median conduit size was 14mm (range, 10-18). RESULTS: At a mean follow-up of 23+/-5 months, two late deaths (8%) have occurred. Although they were not primarily conduit related, both showed severe conduit stenosis. Twenty-one conduits (84%) showed mild to severe conduit stenosis, regurgitation or both. Two patients underwent balloon dilatation for distal conduit stenosis. Twelve conduits (48%) in 11 patients were removed at a median of 12 months (range, 2-18 months) due to RVOT obstruction in 11 and free conduit insufficiency with pseudoaneurysm in one. The typical findings of the explanted conduits were prominent intimal peel formation at the distal anastomosis without calcification. The actuarial freedom from reintervention at 18 months was 48+/-10%. CONCLUSIONS: Our experience of the SPVC with the diameter of 14mm or less has revealed a high incidence of distal conduit stenosis due to intimal peel formation resulting in early conduit failure. These findings have led us to abandon its use when other options are available.  相似文献   
100.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号